For many years it has been a common practice to sift flour and similar granulated or powdery food ingredients, such as powdered sugar, preparatory to or following baking. Such sifting is typically done by shaking a supply of the ingredient disposed atop a sieve or screen of a type having small interstices. Sifters of such simple construction are comprised merely of a tubular casing, a screen mounted at the bottom of the casing and a handle. In use the casing is filled or partially filled with flour or the like and the loaded sifter then manually shaken whereupon the flour is sifted through the screen and any unsifted residue discarded. Other sifters of simple construction are designed to permit limited relative movement between the screen and casing. Though these are usually hand drive, they have been provided with electric motor means such as that sifter illustrated in U.S. Pat. No. 266,819.
Since sifting of flour can take a considerable amount of time, leading to manual fatigue, sifters have been devised which have their own electric drive means. Exemplary of such are those shown in U.S. Pat. Nos. 3,063,563 and 3,964,646. Other sifters have been developed for connection to the electric drive means of other types of household appliances. For example, U.S. Pat. Nos. 2,074,162, 2,521,034 and 2,537,852 disclose sifters which are adapted to be detachable coupled with the electric drive of small kitchen appliances of the type that operate while set upon a supporting surface such as a counter top. These other types of appliances have been mixers, beaters and the like such as the famous Mix-Master. These specialty type sifters, however, have met with but limited commercial acceptance due to the costs associated with the construction of their complex coupling mechanisms as well as to their lack of portability, versatility, and to difficulties encountered in cleaning them.
Accordingly, it is seen that a need remains for a sifter of a type which may be readily coupled to the electric drive of a commonly available kitchen appliance which overcomes the just described problems and limitations of the prior art. It is to the fulfillment of such a need that the present invention is therefore primarily directed.